1. Pharmacy math tutoring exam 6
Jillian Schmidt

2. Chapter 12: Electrolyte solutions: milliequivalents, millimoles, milliosmoles
Objectives:
Calculate the millimoles from atomic or formula weight
Convert between milligrams and millimoles
Calculate the milliequivalents from atomic or formula weight
Convert between milligrams and milliequivalents
Convert between millimoles and milliequivalents

3. Millimoles One mole : molecular weight in grams
One millimole : molecular weight in milligrams

4. Osmolarity Unit used to measure osmotic concentration
Millimoles of solute per liter of solution
Nonelectrolytes
Compounds that do not dissociate in solution
Each 1 mmol contributes 1 mOsmol
Electrolytes
Separate into ions
Each 1 mmol contributes 2 mOsmol (one from each ion)
mOsmol/L = (wt of substance in g/L / MW in g) * number of species * 1000

5. milliequivalent
Used to express the concentration of electrolytes in solution
Relates to the total number of ionic charges in solution
Determine the moles or millimoles and multiply by the valence
Valence- amount of charge of an ion
Equivalents (Eq)
The number of univalent counter ions needed to react with each molecule of a substance
Example: HCl has 1 equivalent per mole, 1 mole of H+ reacts with one mole of Cl-
For a given compound, the mEq of cations equals the mEq of anions

6. milliequivalents
mEq represents the amount of a compound in milligrams equal to 1/1000 of its molecular weight taking into account the valence of the ions
mEq = (mg x valence) / (molecular weight)

7. 0.9% NaCl
9g/1000mL
9000 mg/L
mEq?
(9000mg/L)/58.5mg/mmol= 154mmol/L*1mEq/mmol= 154mEq/L *1L/1000mL=
58.5 g/mol *1000mg/g * 1mol/1000mmol
58.5 mg/mmol

8. 2 mEq/ml KCl
Mg?
2mEq/mL * 1mmol/1mEq= 2mmol/mL
2mmol/mL*74.5mg/1mmol= 149mg/mL